The present invention is directed to a microprocessor controlled sensor system for an apartment house. The invention periodically collects data for use in evaluating the operation of the apartment house heating system. Apartment temperature data is obtained by sampling a single temperature sensor located in the return air plenum of an apartment at preselected sample intervals of time. A single on/off calling device in the apartment is also sampled at the preselected sample intervals of time. Sampling of the temperature sensors and on/off calling devices for all of the apartments is controlled by a single microprocessor unit which is conveniently located at a remote working area. No data processing circuitry is located in any of the apartments. The collected data is stored on a day-by-day basis in a conventional tape cassette.
Degree day data loggers are known in the art. For example, see U.S. Pat. No. 3,911,746. The data logger described therein consists of a bridge circuit provided with a temperature sensing element in one arm, a comparator, and an elapsed time meter. Any change in temperature indicated by the bridge output is compared to a reference temperature by the comparator, and the comparator output is accumulated to provide an indication of degree days with respect to the reference temperature. Apparently, the data logger can accumulate degree days for only a single temperature sensing element.
The allocation of fuel costs among plural apartments in an apartment house is also known. For example, see U.S. Pat. No. 4,002,890. Corresponding to each apartment, there are several temperature sensors which are used to compute a weighted mean temperature for the apartment. Apparently, each apartment requires its own analog computer circuit to effect the allocation of fuel costs based on the weighted temperatures.
The computation of internal degree days with respect to an external temperature norm is also known. See U.S. Pat. No. 2,652,724.
An advantage of the present invention is that data indicating the performance of a heating system for an apartment house is automatically collected for evaluation on a day-by-day basis.
Another advantage of the invention is that it can be easily and rapidly installed in an apartment house without the addition of elaborate or expensive hardware components.
A further advantage of the invention is that all of the data processing elements may be located in a remote working area.
Other advantages appear hereinafter.